chairwoman Patricia Dunn acknowledged she authorized the private investigation that has plunged her company into turmoil. Dunn defended her actions but apologized for the techniques that were used to determine who was leaking company secrets to the media.

Wall Street Journal reporter Joann Lublin says investigators hired by H.P. allegedly impersonated board members and reporters to obtain information. "Board members got spied on. And their phone records were pried loose without their knowledge."

Hewlett-Packard Chair Resigns But Threat of Criminal Charges Remains

Using fake identification to obtain information is called "pretexting." Private investigator Terry Lenzner says it should not have been done. "One of the standard rules is, if you get information that you can't use because the methodology you used to obtain it is too revolting to a judge or jury, then don't do it."

Hewlett-Packard Chair Resigns But Threat of Criminal Charges Remains

California Attorney General Bill Lockyer says, not only is it unethical, it's also illegal. He warns charges are likely against company insiders and contractors. "If it wasn't illegal, it was colossally stupid and I think people are offended."

Hewlett-Packard Chair Resigns But Threat of Criminal Charges Remains

Dunn said she was angry about leaks of confidential board discussions. She will step down as chairman in January but will remain as a board director.

Technology analyst Rob Enderle believes Dunn acted in the best interest for the company. "The end result was the buck stopped at her desk and she did what was best for the company which is, I think, historically consistent with what she's done so far. She's been one of the board members who drove through the changes that brought H.P. up to the level where it currently is."

A 21-year board member who admitted leaking information to reporters also has resigned. The probe is expected to widen as federal agents join the investigation. The California attorney general says it may file charges in about a week.